The demand for propylene impact copolymers with high melt flow continues to increase as the need for more sophisticated polymers continues to grow. In-reactor propylene impact copolymers are copolymers produced by way of polymerization, and do not include visbreaking, for example. It is difficult to produce high melt flow propylene impact copolymers directly by polymerization. Conventional polymerization catalysts typically require the use of very high hydrogen concentrations for the formation of a matrix phase polymer with a melt flow greater than the melt flow of the final propylene impact copolymer. In many cases, provision of a high hydrogen concentration is not possible due to reactor operability limits, safety concerns, and/or economic considerations.
Desirable is a polymerization process for the production of a high melt flow propylene impact copolymer. Further desired is a process for the production of a high melt flow propylene impact copolymer with high impact strength. Further desired is a process for the production of a high melt flow propylene impact copolymer with high impact strength with reduced risk, or no risk, of process disruption.